The 15 most common mistakes in professional emails (and how to avoid them)

You proofread your email twice, hit Send, and one minute later you see it. The typo. It was there the whole time, sitting in plain sight right above your signature. Too late now.

Take comfort in this: everyone makes mistakes in their emails, including people who are genuinely good at spelling. The good news is that it tends to be the same ones over and over. Here are fifteen of them, the ones that actually show up in work inboxes every single day, each with the correct version and a quick trick to remember it.

The apostrophe traps

1. “Its” vs “it’s”
The most common mistake in the English language, full stop. It’s means “it is” or “it has”. Its shows possession. The test takes two seconds: read the sentence with “it is”. If it works, you want the apostrophe.

2. “Your” vs “you’re”
Same logic. You’re is short for “you are”, while your means it belongs to you. “Your welcome” thanks nobody; “you’re welcome” does.

3. “Their”, “there” and “they’re”
Three words, one sound. Their report, over there, and they’re (they are) running late. When in doubt, expand the contraction and see if the sentence survives.

4. Apostrophes in plurals
“The report’s are attached” hurts to read. Plurals never take an apostrophe: the reports are attached. Apostrophes mark possession or contraction, nothing else.

The sound-alikes

5. “Should of”
It comes from the sound of “should’ve”, but it has never been correct. Always should have, would have, could have.

6. “Loose” vs “lose”
You lose a client, a file or a bet. Loose is the opposite of tight. “We can’t afford to loose this deal” says something quite different from what you meant.

7. “Then” vs “than”
Than compares: better than expected. Then orders things in time: we met, then we signed. Comparison gets an a, time gets an e.

8. “Affect” vs “effect”
In everyday emails, affect is the verb (“this will affect the deadline”) and effect is the noun (“the effect on the deadline”). There are rarer exceptions, but this rule covers just about every email you will ever write.

9. “Advice” vs “advise”
You advise someone (verb, sounds like “z”), and you give them advice (noun, sounds like “ice”). “Please advice” appears in an astonishing number of inboxes.

The spelling classics

10. “Alot”
Not a word. It is always two: a lot. If you would write “a little”, write “a lot” the same way.

11. “Definately”
The word is definitely, built on “finite”. No a anywhere in the middle, however tempting it sounds.

12. “Seperate”
It is separate, with “a rat” hiding in the middle: sep-a-rat-e. Silly, but it sticks.

13. “Recieve”
The old rule still works: i before e, except after c. So it is receive, and received, and receipt.

The grammar slips

14. “Me and John will attend”
Take John out of the sentence and listen: “me will attend”. The correct form is John and I will attend. And the mirror trap exists too: “please contact John or I” should be “John or me”, because you would say “contact me”.

15. “The team have finalised there proposal”
Two slips in one, and it happens more often than you would think once the sentences get long. The longer the email, the easier it is for a “there” to sneak in where a “their” belongs. Fatigue writes half of these mistakes.

Why these mistakes matter (a little) more than you think

Let’s be honest: nobody ever lost a client over one “alot”. The problem is accumulation. An email carrying three or four of these sends a signal of carelessness, however unfair that is, and sometimes that email is the only impression the other person has of you. A clean message, on the other hand, goes unnoticed. Which is exactly the point.

Proofreading helps, of course. But we are terrible at proofreading our own writing: the brain reads what it meant to write, not what is actually on the screen. That is why the typo jumps out after you hit Send, once you finally read your email the way a stranger would.

What if something proofread for you?

That is exactly what Correctify does: select your text in Outlook, Word, Gmail or any Windows app, press a keyboard shortcut, and the AI fixes the mistakes while leaving your formatting untouched. All fifteen traps in this list? It catches every one of them, including the sneaky sound-alikes. The app is free and works with your own API key.

In the meantime, keep this list handy. The first three alone, its, your and their, probably account for half the mistakes flying around your inbox right now.